Most acronyms are convoluted, forced and cheesy. However, there is one that is both funny and wise: K.I.S.S. “Keep it simple, stupid”. In it’s most basic sense, the coherence principle is K.I.S.S.. When creating instructional multimedia, the most positive post-test retention results will come from lessons that avoid extraneous information (Clark, 2011). That information may be audio, images or text. It seems to make sense that adding sound effects would help keep learners engaged. It is very tempting to add flashy graphics to catch the attention of learners. Extra information seems like it can only enrich. However well intended, these extras can all serve to clutter instruction by distraction, disruption and seduction (Clark, 2011).

Recently, I observed a well intentioned teacher deliver a strong slideshow that was derailed by one fatal flaw. The flaw was the most obvious example of distraction in a presentation that I can remember seeing. The lesson was a straightforward examination of the roots of the Protestant Reformation. Students were expected to walk away with basic facts regarding the lives and teachings of John Calvin and Martin Luther. With each new piece of information and each new slide, the computer speakers rattled out wild noises of explosions, bullets whizzing by and lasers firing. It was surprising and the juxtaposition with the words (ideas like predestination and the 95 Theses) was comical. The kids laughed, imitated and made dry remarks. As time went on, I found it annoying and grating, but the kids continued to find it mildly amusing.

The teacher believed the addition of the crazy sounds to be successful. It was a dry topic, but kids laughed through the whole thing. It must have kept their attention. The next day, when the teacher asked students what they remember from the day before, most of the kids could only come up with laser noises and cannons firing. The sounds had distracted the students from the actual point of the lesson.

Learning can also be disrupted with images. A disruption is like a break in the chain of learning that prevents students from making the proper connections. Imagine a presentation on the causes of World War 1. There are quite a few causes to be taught and they are complex. The final event that sets off the war is the assassination of Franz Ferdinand. This event creates a domino effect that leads to many of the major European powers declaring war on each other. It might seem to make sense, as a series of slides list the causes of World War 1, to insert an image of dominos between the information on Franz Ferdinand being killed and countries declaring war. However, this image may disrupt the connections that the previous slides were attempting to make. Instead of the series of events leading up to the start of World War 1, the last image in learners’ minds before the war breaks out is an image of dominos.

The presentation of a complex series of causes is interrupted by a metaphorical image placed right before the big effect.

Finally, text can interfere with learner retention by adding unnecessary or unrelated information. Text can seduce the learner. When I say seduce, one might imagine a playful blonde with snow soft skin melting under a fiery gaze or the way dancing candlelight catches a blue eye in a dark room or how the heart rises, lips blossom and body dews like a May morning in the spring of a first kiss, but I am not referring to that kind of seduction. After that aside, readers are likely thinking about something completely unrelated to slideshow presentations and educational theory. That was an example of how text can distract a learner from the key information. Unessential text may be added to “spice up” a presentation, but beware that it can trigger a completely unintended series of thoughts, memories and emotions in the learners. It is best to keep all text on target and directly related to the lesson objectives.

Clark and Mayer (2011) found that teachers that avoid extraneous audio can likely expect to see retention rates 20% higher than if extraneous audio was included. So while it may be tempting to add some animal sounds to an e-lesson on the animal kingdoms, the coherence principle says to leave the animal noises out.

Clark and Mayer (2011) also found that beyond limiting extraneous images, images should be kept simple. “It seems that learners (in the video group) were overwhelmed with the amount of realistic detail and failed to come to a proper understanding of the process…” (p. 166). So, while a Bohr model does not accurately reflect many of the properties of an atom, teachers that use the Bohr model with novice learners are likely to have success because of it’s simplicity. Using the Bohr model in favor of a more complex, but accurate atomic model is an example of proper use of the coherence principle.

Whether extra words are added for technical depth, to expand on key ideas or just to grab the interest of the reader, Clark and Mayer (2011) recommend that they are omitted from presentations because they will actually reduce retention of the intended objectives. A teacher looking to build a well structured media presentation that follows the coherence principle must think like an editor and review every piece of text to remove any information that does not directly relate to the core objectives. As interesting as Ernest Hemingway’s relationship with Martha Gellhorn, feud with F. Scott Fitzgerald and eventual suicide might be, if it is a lesson on the themes and motifs of For Whom the Bell Tolls, those details should be removed.

The coherence principle is good teaching and directly aligned to previous multimedia principles studied. For example, the redundancy principle suggests that information should be presented in audio or text, not both. (Clark, 2011) If we have text and matching audio, it is mental clutter . We are occupying two brain pathways with identical ideas. Educators do need to be careful. For example, the multimedia principle suggests that learners do better with both words and graphics. This might cause a teacher to insist on finding graphics for all their text and all their instructional points. This could lead to an obvious violation of the coherence principle which advises against adding images just for the sake of having images. The takeaway is that it is best practice to have images if they are directly connected to the key objectives, but best practice to abstain from images that are superfluous. Sometimes that can be a difficult decision and it is where the discretion of the educator comes into play to ensure all the principles are in confluence as much as is possible.

Along with the other multimedia principles, the coherence principle must work in harmony with psychological theories. The cognitive theory of learning suggests that people have a limited capacity for processing information (Clark, 2011). This is precisely the reason that Clark and Meyers suggest removing extraneous audio, visuals and text. This extra information can overload cognitive systems or cue the cognitive systems to focus in the wrong places or on the wrong information. The more stimuli presented and the more options presented, the more opportunities students are given to venture down the wrong paths.

The coherence theory is just a theory and not a law. While it has evidence to support it, there are limitations in the understanding of it. Clark and Mayer acknowledge that the research is geared towards short lessons amongst novice learners (2011). Would the addition of attention grabbing graphics and sounds improve attention and retention over lengthier lessons where it is more likely that the learner loses interest? Are the people that have volunteered for the experiment more intrinsically motivated than a student in a natural environment that is possibly being forced to take a class or view a presentation? Would a learner with a strong knowledge base benefit from more technical details being presented? There are many questions without complete answers which is why the coherence theory should guide teaching, but not rule teaching.

In general, I am a believer in coherence theory. I think a lot of teachers cloud their key objectives with extraneous information. It is something that I see and do regularly. However, over courses that cover weeks and months, there is likely a place for some extra information and some “jazz” to shake up presentations. An experimental group that comes in for less than an hour with no distractions isn’t the same as a class of kids that have been in school for hours and are surrounded by friends and drama.

Additionally, there does seem to be a risk that K.I.S.S. becomes “keep it stupid simple”. By removing a lot of what is considered “excess” information, is the content being dumbed down? Are we “teaching to the test”? Is the preparation for single isolated tests happening at the expense of teaching kids bigger lessons on how to prepare for life where information won’t be so streamlined for them? Are those extra details we remove the pieces that brought the content to life for some students? Inspired others?

The dogmatic adherence to any principle is poor practice compared to constant formative self-evaluation. Heraclitus once said, “no man steps into the same river twice”. No teacher truly teaches the same lesson twice as the students, teacher, and context always change. I would suggest teachers pay close attention to their students, monitor assessment scores, interest levels, attitudes, etc. Those observations and scores, with the coherence principle and and a host of other researched principles/strategies should be used by teachers in balance to keep them afloat at the conflux of teaching and learning.